clam
I. clam1 /klæm/ BrE AmE noun [countable]
[Date: 1500-1600; Origin: clam 'two-part fastener' (14-20 centuries), from Old English clamm 'chain, rope, etc. for tying something up'; from the tight shutting of a clam shell]
1. a ↑shellfish you can eat that has a shell in two parts that open up:
clam chowder (=a type of soup)
2. as happy as a clam American English informal very happy
3. American English informal someone who does not say what they are thinking or feeling
II. clam2 BrE AmE verb (past tense and past participle clammed, present participle clamming)
clam up phrasal verb
informal to suddenly stop talking, especially when you are nervous or shy:
A sensitive child is likely just to clam up.
